The present invention relates generally to methods of retrieving disk information from an optical disk, such as a CD-R or CD-RW disk (which will hereinafter be generically called a xe2x80x9cCD-R/RWxe2x80x9d disk), and controlling access and recording to a CD-R/RW disk, and optical disk recording apparatus for recording desired information onto a CD-R/RW disk. More particularly, the present invention is concerned with a technique which allows disk information to be obtained quickly and accurately from a multi-session-recorded CD-R/RW disk using PMA (Program Memory Area) information recorded in a PMA area of the optical disk and which permits access to each desired track and additional writing (including overwriting) of a track on the basis of the thus-retrieved disk information. Note that the terms xe2x80x9cdisk informationxe2x80x9d used in the context of the present invention refers to such information recorded in the PMA and TOC (Table Of Contents) areas of the CD-R/RW disk.
Multi-session recording is standardized as an example of various recording schemes applicable to the CD-R/RW disks. The multi-session recording scheme is characterized by recording a plurality of sessions on a CD-R/RW disk, each of which is a set of a lead-in area, a program area and a lead-out area. More specifically, in each of the sessions, the lead-in area has stored therein lead-in information such as TOC information of the individual tracks present in that session. In many cases, the program area in the session has stored therein information including user data and a path table continuing from a preceding session. Further, according to the multi-session recording scheme, the sessions are recorded on the disk one after another from the disk""s inner circumference to the outer.
Therefore, the conventional CD-R drive, CD-RW drive or drive having a combination of the functions of the CD-R and CD-RW drives (hereinafter xe2x80x9cCD-R/CD-RW drivexe2x80x9d) are designed in such a way that upon insertion or loading of a disk into the drive, Q subcode information in the innermost lead-in area is read out in order to retrieve all the disk information and latest user data (path table recorded in the last session) and then, once the disk in question has been identified as a multi-session-recorded disk, a xe2x80x9cdisk searchxe2x80x9d is conducted to search for all the disk information up to the last session and the path table recorded in the last session.
Among various approaches for searching for all the disk information up to the last session is to sequentially read the lead-in areas of the individual sessions. Namely, according to this approach, the TOC information of the first or leading session is read out along with program-starting-time information of the second session, then access is made, on the basis of the program-area-starting-time information of the second session, to the lead-in area of the second session to read out the TOC information of the second session along with program-starting-time information of the third session, then access is made, on the basis of the program-area-starting-time information of the third session, to the lead-in area of the third session to read out the TOC information of the third session along with program-starting-time information of the fourth session, and so on. Such procedures are repeated to sequentially access the lead-in areas of the individual sessions of the disk. When it is determined that there is no more data recorded in the lead-in area of a specific session accessed, the specific session is considered to be an unrecorded portion and the session immediately preceding the specific session is judged to be the last session. Once all the disk information up to the last session has been retrieved, access is made to the path table and the like recorded in the last session on the basis of the disk information of the last session, to thereby retrieve the path table and the like from the last session. Only after completion of the retrieval of these information, access to the individual tracks and additional writing of a new track become possible.
Further, the conventionally-known techniques for erasing an entire recorded surface of the CD-RW disk have two major types, the xe2x80x9cfull erasexe2x80x9d and xe2x80x9cquick erasexe2x80x9d. The xe2x80x9cfull erasexe2x80x9d technique is characterized by writing logical xe2x80x9c0xe2x80x9ds onto the entire recorded surface and has the advantage of being able to completely erase all the recorded contents; however, this technique is disadvantageous in that it takes a long erasing time. For example, where the records are to be erased from a 74-minute disk at the standard (non-increased or non-reduced) speed, the full erase would take at least 74 minutes or more. The xe2x80x9cquick erasexe2x80x9d technique, on the other hand, is characterized by erasing information recorded in the PMA area existing inward of the lead-in area of the first session as well as information recorded from the lead-in area of the first session to a pre-gap in such a way that information recorded outward of the pre-gap is left unerased; note that the PMA area is an area for storing the PMA information pertaining to the currently-recorded track, such as starting and ending times etc. of the track, each time a succession of recording procedures is suspended. Also note that the PMA area also keeps storing the disk information of each already-completed session until the full erase or quick erase is instructed. Once the recorded information is erased from the PMA area and lead-in area of the first session, a multi-session-capable optical disk apparatus, having installed therein the CD-RW disk, is no longer able to obtain any information from either the initially accessed PMA area or the lead-in area of the first session, so that the optical disk apparatus determines that all the tracks have been erased. As a consequence, the quick erase technique can achieve the same advantage as the full erase technique by erasing operations of a shorter time.
However, with the above-mentioned approach of sequentially reading the lead-in areas of the individual sessions, a very long time would be taken to retrieve the information of all the tracks if the disk has a great many sessions, which would undesirably result in a long waiting time before reproduction or additional writing of a track is permitted.
Further, because the quick-erased CD-RW disk still has data on and after the first track of the first session left unerased, the following inconveniences tend to be encountered in newly performing multi-session recording. Namely, upon loading of a CD-RW disk having data recorded thereon up to the first session after the quick erasure, the multi-session-capable optical disk apparatus retrieves program-area-starting-time information of the second session from the lead-in area of a new first session and, on the basis of the starting-time information, accesses particular addresses where the lead-in area of the second session is supposed to exist. If certain data of any of the old sessions, which existed before the quick erasure, is still left at the accessed addresses, then the optical disk apparatus sometimes erroneously retrieves the left data. Particularly, if the left data is data of the lead-in areas of some old session, the optical disk apparatus would take it to be data of the lead-in area of the second session, on the basis of which it sequentially reads the data of the lead-in areas of the old sessions. By so doing, the optical disk apparatus would retrieve all the TOC information of the old sessions and also obtain the path table of the last one of the old sessions on the basis of the TOC information of the last session. Thus, although the new first session has now been recorded on the optical disk, no access can be made to individual files of the new first session due to the fact that the path table obtained includes no information corresponding to the new first session. Another inconvenience is that a new second session can not be recorded on the disk immediately after the new first session.
Furthermore, because no erasure takes place in the CD-R disk, arrangements have to be made to read out and reproduce all the records from the CD-R disk even where the disk failed in PMA recording.
The present invention provides solutions to the above-discussed problems of the conventional techniques. Namely, it is an object of the present invention to provide an information retrieving method, access controlling method and recording controlling method for use with an optical disk and an optical disk recording apparatus which permit quick retrieval of all recorded information from the optical disk in a case where the optical disk is a CD-R disk, or reliable avoidance of erroneous retrieval of old session information that should have been erased from the optical disk in a case where the optical disk is a CD-RW disk, and which permit access to individual tracks and additional writing of a track on the basis of the retrieved disk information.
To accomplish the above-mentioned object, the present invention provides a method of retrieving disk information from an optical disk, which comprises the steps of: accessing a given location within an innermost lead-in area of a CD-RW disk, to retrieve a starting time of the innermost lead-in area from ATIP information; accessing a starting point of a PMA area of the disk, on the basis of the starting time of the innermost lead-in area, to retrieve PMA information; then, on the basis of a time interval between adjoining tracks represented by the PMA information, dividing the tracks into a plurality of sessions and accessing a lead-in area of the last session to determine presence/absence and validity of lead-in information in the last session; and then, only when the lead-in information of the last session is judged to be valid, retrieving the lead-in information of the last session as valid lead-in information.
According to the disk information retrieving method arranged in the above-mentioned manner, the disk information of the individual sessions, such as respective track numbers, starting and ending times of tracks, is obtained from the PMA information recorded in the PMA area (for the first and last sessions, however, the disk information recorded in their respective lead-in areas may be used), so that the disk information of the individual sessions can be obtained in a very short time. Further, because a determination is made, for the last session, as to presence/absence and validity of lead-in information therein, the present invention can reliably avoid erroneous retrieval of information of any old session that should have been erased from the disk.
The validity of the lead-in information of the last session may be determined on the basis of a combination of one or more of the following:
presence/absence of an HF signal,
presence/absence of a lead-in area format, and
presence/absence of a logic erasure format in the lead-in area of the last session; and
comparison between TOC information included in the lead-in information of the last session and the PMA information.
Further, in this case, the above-mentioned comparison between the TOC information included in the lead-in information of the last session and the PMA information may be made on the basis of one or more of the following comparisons:
comparison between track numbers included in the TOC information and PMA information;
comparison between track starting times included in the TOC information and PMA information;
comparison between an ending time of a track included in the PMA information and a starting time of a next track included in the TOC information; and
comparison between an ending time of a last track included in the PMA information and a lead-out starting time included in the TOC information.
The present invention also provides a method which is directed to, after retrieval of disk information from the optical disk in accordance with the above-mentioned disk information retrieving method, controlling access to individual tracks of the optical disk on the basis of the PMA information included in the retrieved disk information.
The present invention also provides a method which is directed to, after retrieval of disk information from the optical disk in accordance with the above-mentioned disk information retrieving method, controlling recording on the optical disk through the steps of: when the lead-in information of the last session is judged to be valid, permitting additional writing of a next session on condition that a B0 pointer included in Q subcode information of the lead-in information of the last session is other than FF: FF: FF; and when there is no lead-in information in the last session or the lead-in information of the last session is judged to be invalid, permitting additional writing of a track next to the last session or recording, onto the last session, of lead-in and lead-out information to complete the last session.
According to another aspect of the present invention, there is provided an optical disk recording apparatus which includes a control section for performing any one of the above-mentioned methods at a given time after loading of a CD-RW disk into the recording apparatus.
According to still another aspect of the present invention, there is provided a method of retrieving disk information from an optical disk, which comprises the steps of: accessing a given location within an innermost lead-in area of a CD-R disk, to retrieve a starting time of the innermost lead-in area from ATIP information; accessing a starting point of a PMA area of the disk, on the basis of the starting time of the innermost lead-in area, to retrieve PMA information; on the basis of a time interval between adjoining tracks represented by the PMA information, dividing the tracks into a plurality of sessions and accessing a lead-in area of the last session to determine presence/absence lead-in information in the last session; when the lead-in information is present in the last session, determining whether a B0 pointer is present in Q subcode information of the lead-in information; then, when the B0 pointer is present in the Q subcode information of the lead-in information, accessing a lead-in area of a next session on the basis of a starting time of a program area of the next session included in the Q subcode information and determining presence/absence of lead-in information in the next session; and, then, when the lead-in information is present in the next session, retrieving the lead-in information from the next session. In this manner, readout of the lead-in information across every adjoining sessions can be sequentially performed up to a particular one of the sessions where the lead-in information is retrieved any longer or where the B0 pointer is retrieved any longer from the lead-in information.
According to the disk information retrieving method arranged in the above-mentioned manner, the disk information of the individual sessions, such as respective track numbers, starting and ending times of tracks, is obtained from the PMA information recorded in the PMA area (for the first and last sessions, however, the disk information recorded in their respective lead-in areas may be used), so that the disk information of the individual sessions can be obtained in a very short time. Further, even when there is failure in the PMA recording, the disk information can be retrieved appropriately by the sequential readout of the lead-in information.
The present invention also provides a method which is directed to, after retrieval of disk information from the CD-R disk in accordance with the above-mentioned disk information retrieving method, controlling access to individual tracks of the optical disk on the basis of the PMA information included in the retrieved disk information or, for each session for which no such PMA information is included in the disk information, on the basis of the lead-in information.
The present invention also provides a method which is directed to, after retrieval of disk information from a CD-R disk in accordance with the above-mentioned disk information retrieving method, controlling recording on the optical disk through the steps of: when lead-in information is present in an outermost session of said optical disk, permitting additional writing of a next session on condition that a B0 pointer is included in Q subcode information of the lead-in information of the outermost session; and when there is no lead-in information in the outermost session, permitting additional writing of a further session next to the outermost session or recording, onto the outermost session, of lead-in and lead-out information to complete the outermost session.
According to still another aspect of the present invention, there is provided an optical disk recording apparatus which includes a control section for performing any one of the above-described CD-R-disk-related methods at a given time after loading of a CD-R disk into the recording apparatus.
According to still another aspect of the present invention, there is provided an optical disk recording apparatus having a combination of the functions of CD-R and CD-RW drives (i.e., xe2x80x9cCD-R/CD-RW drivexe2x80x9d). This drive includes a control section which, at a given time after loading of an optical disk into the recording apparatus, identifies a type of the loaded optical disk and performs any one of the above-described CD-RW-disk-related methods when the loaded optical disk is identified as a CD-RW disk but performs any one of the above-described CD-R-disk-related methods when the loaded optical disk is identified as a CD-R disk.